My test results with 720p / 1080p H.264 (+ Vimeo YouTube):
- Windows 7 with Nvidia graphics: CPU noticeable relief - Mac OS X 10.6.2 on Mac Book Pro with Nvidia graphics: no CPU discharge - Linux (Ubuntu 8.04) Intel Graphics: 1 Picture every 5 seconds. - Linux (Ubuntu 9.10) on Nvidia Graphics: magenta-colored rectangles flicker through the Picture.
For all platforms: stop after some time videos with one Stillimage. You can not move at all in the world the player to play beyond this point to next.
Conclusion: This version is expected, not quite finished. That is why I initially remain the Flash Player 10.0. I hope the trend is positive and the next player will again be used universally on any hardware.